Fiona B McDonald

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Chronic intermittent hypoxia (CIH) causes upper airway muscle dysfunction. We hypothesized that the superoxide generating NADPH oxidase (NOX) is upregulated in CIH-exposed muscle causing oxidative stress. Adult male Wistar rats were exposed to intermittent hypoxia (5% O2 at the nadir for 90 s followed by 210 s of normoxia), for 8 h per day for 14 days. The(More)
Intermittent hypoxia is a feature of apnea of prematurity (AOP), chronic lung disease, and sleep apnea. Despite the clinical relevance, the long-term effects of hypoxic exposure in early life on respiratory control are not well defined. We recently reported that exposure to chronic intermittent hypoxia (CIH) during postnatal development (pCIH) causes upper(More)
Obstructive sleep apnoea syndrome (OSAS) is a devastating respiratory control disorder more common in men than women. The reasons for the sex difference in prevalence are multifactorial, but are partly attributable to protective effects of oestrogen. Indeed, OSAS prevalence increases in post-menopausal women. OSAS is characterized by repeated occlusions of(More)
Nitric oxide (NO) is an important modulator of striated muscle function. Nitric oxide synthase (NOS) expression and activity is altered by hypoxia and NO is implicated in respiratory muscle remodeling following chronic sustained hypoxia. We sought to determine if NO is implicated in upper airway dilator muscle adaptation to chronic intermittent hypoxia(More)
Sudden infant death syndrome (SIDS) is one of the most common causes of postneonatal infant mortality in the developed world. An insufficient cardiorespiratory response to multiple environmental stressors (such as prone sleeping positioning, overwrapping, and infection), during a critical period of development in a vulnerable infant, may result in SIDS.(More)
In unrestrained whole body plethysmography, tidal volume is commonly determined using the barometric method, which assumes that temperature and humidity changes (the 'barometric component') are solely responsible for breathing-related chamber pressure fluctuations. However, in small animals chamber pressure is also influenced by a 'mechanical component'(More)
Alterations to the supply of oxygen during early life presents a profound stressor to physiological systems with aberrant remodeling that is often long-lasting. Chronic intermittent hypoxia (CIH) is a feature of apnea of prematurity, chronic lung disease, and sleep apnea. CIH affects respiratory control but there is a dearth of information concerning the(More)
NEW FINDINGS What is the central question of this study? Chronic intermittent hypoxia (CIH) is a dominant feature of respiratory control disorders, which are common. We sought to examine the effects of exposure to CIH during neonatal development on respiratory muscle form and function in male and female rats. What is the main finding and its importance?(More)
RATIONALE Obstructive sleep apnoea syndrome (OSAS) is a debilitating condition characterized by recurrent occlusions of the pharyngeal airway during sleep accompanied by arterial hypoxaemia. Upper airway muscle dysfunction is implicated in the pathophysiology of OSAS. Pharmacological agents that improve muscle contractile and endurance properties may have(More)
We sought to test the hypothesis that chronic intermittent hypoxia (CIH)-a feature of sleep-disordered breathing in humans-impairs reflex recruitment of the genioglossus (GG, pharyngeal dilator) during obstructive airway events. Adult male Wistar rats were exposed to 20 cycles of normoxia and hypoxia (5% O2 at nadir) per hour, 8h a day for 7 days (CIH,(More)